To see if recombinant human TSH (Thyrogen) can be used to stimulate uptake of radioactive iodine in patients previously surgically treated for (well-differentiated) thyroid cancer. To compare conventional (hypothyroid) radioactive iodine scans with two dose protocols using Thyrogen stimulated radioactive iodine scans. To see if Thyrogen stimulation of thyroglobulin can be used as an adjunct to the diagnosis of thyroid carcinoma. To study safety of Thyrogen. Ultimately to see if Thyrogen stinulation can replace the hypothyroid state currently required for radioactive iodine scanning and therapy in patients with well differentiated thyroid cancer.